Replication of data processing systems to maintain operational continuity is now required almost everywhere. The costs incurred during downtime when information technology equipment and services are not available can be significant, and sometimes even cause an enterprise to halt operations completely. With replication, aspects of data processing machines that may change rapidly over time, such as their program and data files, physical volumes, file systems, etc. are duplicated on a continuous basis. Replication may be used for many purposes such as assuring data availability upon equipment failure, site disaster recovery or planned maintenance operations.
Replication may be directed to either the physical or virtual processing environment and/or different abstraction levels. For example, one may undertake to replicate each physical machine exactly as it exists at a given time. However, replication processes may also be architected along virtual data processing lines, with corresponding virtual replication processes, with the end result being to remove the physical boundaries and limitations associated with particular physical machines.
Use of a replication service as provided by a remote or hosted external service provider can have numerous advantages. Replication services can provide continuous availability and failover capabilities that are more cost effective than an approach which has the data center operator owning, operating and maintaining a complete suite of duplicate machines at its own data center. With such replication services, physical or virtual machine infrastructure is replicated at a remote and secure data center.
In the case of replication services to virtual target, a virtual disk file containing the processor type and configuration, operating system, data, and applications for each data processor in the production environment is created and retained in a dormant state. In the event of a disaster, the virtual disk file is moved to a production mode within a Virtual Data Center (VDC) environment at the remote and secure data center. Applications and data can then be accessed on the remote VDC, enabling the service customer to continue operating from the cloud while recovering from a disaster.
From the perspective of the service customer, the replication service provider thus offers a Recover to Cloud (R2C) service that is provided much like an on-demand utility (much like the electricity grid) over a network (typically the Internet). This enables a data center operator to replicate critical servers and applications in his production environment to the cloud, with the VDC environment being activated to bring up the corresponding virtual machines and applications via the cloud in the event of a disaster.